Ultraviolet-curing organopolysiloxane compositions known for the purpose of preventing adhesion between tacky substances and the surfaces of various types of substrates (e.g., paper, synthetic resin-laminated paper, synthetic resin films, knitted and woven fabrics, metal foils, and so forth) are known in the art. For example ,Japanese Patent Application Laid Open [Kokai or Unexamined] Number Sho 50-61386 [61,386/1975] discloses a composition comprised of a mercapto group-containing organopolysiloxane, a vinyl-containing organopolysiloxane, and a photosensitizer. Japanese Patent Application Laid Open Number Sho 61-20471 [20,471/1986]) discloses a composition comprised of a mercapto group-containing organopolysiloxane and a photosensitizer. Additionally known are organopolysiloxane compositions comprised of an alkenyl-containing organopolysiloxane, a mercapto group-containing silane, a platinum group metal compound, and a photosensitizer.
However, these ultraviolet-curing organopolysiloxane compositions suffer from slow curing rates, facile exfoliation or delamination of the cured film due to its poor adhesion to the various types of substrates, a reduction in the tack of the tacky substance (low residual adhesion ratio), and a strong mercapto odor. The present inventors developed the present invention as the result of extensive investigations for the purpose of solving the drawbacks to the prior art.
An object of the present invention is an organopolysiloxane composition which is useful for the formation of a cured release film wherein said organopolysiloxane composition cures rapidly under exposure to ultraviolet radiation to form a cured film that tightly adheres to various types of supports or base materials.